Cyclic processes of producing uci6



March 6, 1956 J. M. CARTER 2,737,439

cYcLIc PROCESSES o? PRODUCING UCL,

Filed Nov. 16, 1943 cocl,

co co (:1: Fig. 1

ans pnooucrs 4f STARTING} s; uouscuun ,5 END {MATERIALS U615 "Urea-AVEuc/ snu. uc/ pnooucr} NZ REACTOR o L14M? GAS SUPPLY PRODUCTS STARTING\UC/ MA TER/ALS 4 REACTOR V 2 084/ ee/ I MOLECULAR END sr/u. PRODUCT\UCIG INVENTOR. James M C arfer ATTORNEY.

United States Patent 2,737,439 CYCLIC PROCESSES 0F PRODUCING UCls JamesM. Carter, Pasadena, Calif., assignor to the United States of America asrepresented by the United States Atomic Energy Commission ApplicationNovember 16, 1943, Serial No. 510,558 11 Claims. (Cl. 23-145) Thepresent invention relates to cyclic processes of producing UCle, andmore particularly to such processes wherein UCls is decomposed into UC14and UCls and the UCL; is then converted into UCls to be recycled.

In the production of UCls employing the process disclosed in U. S.Patent No. 2,572,156, issued toFrancis A. Ienkins on October 23, 1951, acharge of UCls is decomposed in a molecular still, whereby UCle isproduced as a sublimate and UCl4 is produced as a residue. This residueof UCI4 constitutes a by-product and is pro duced in an amountequivalent to approximately 45.7% of the charge of UCl5.

Accordingly, it is an object of the present invention to provide aprocess of producing UCla in which the byproduct U014 is recycled.

Another object of the invention is to provide a process of producingUCls wherein UCls is decomposed into UCIrand UCIS and the 001, isconverted directly into UCls to be recycled.

Another object of the invention is to provide a process of producingUCls, wherein UCIs is decomposed into UCla. and. UCls and the UCL; isconverted into uranium oxychloride, which in turn is converted intoUCl's to be recycled.

A further object of the invention is to provide an improved process ofproducing uranium pentachloride which includes preparing an arbitrarymixture of uranium trioxide, U03, and uranium oxychloride and reactingthe mixture with CCl4. 1

A further object of the invention is to provide a process of producinguranium oxychloride in which UC14 is reacted with dry air at an elevatedtemperature.

The invention, both as to its organization and method of operation,together with further objects and advantages thereof, will best beunderstood by reference to the following specification taken inconnection with the accompanying drawing, in which Figure l. is a flowdiagram of a cyclic process of producing UCle embodying the presentinvention, and Fig. 2 is a flow diagram of amodrfied form of the cyclicprocess of producing UCls.

In accordance with the present invention, UCls is first decomposed intoUCl4 and UCle in the manner disclosed in the previously mentionedJenkins application. More particularly, a suitable charge of U015 isplaced in a molecular still and subjected to a vacuum heating operation,the charge being heated to a temperature within the range 80 to 180 C.and subjected to a reduced pressure between. 1.0- and 10" mm. of Hg.When the charge of UCI is. so treated, it is broken down into U014 andUCls, the UCL; remaining as a residue and the UClo being sublimed. Thisdecomposition of the UC15 takes place substantially quantitatively andmay be written as follows:

This treatment normally requires approximately three hours under theconditions mentioned employing a charge of 100 grams of UCls, wherebythe charge of 1.00 grams of UC15 is converted into approximately 45.7grams, of UC14. and. 54.3 grams of UCle. This treatment is continueduntil substantially all of the UC15 is broken down; thereafter theresidue of U014 and the sublimate of use 2,737,439 Patented Mar. 6, 1956are separately collected. In the present process the UCls constitutesthe end-product, while the UCI4 constitutes a by-product. The UCls thusproduced is then bottled in an atmosphere of CO2 or in a vacuum forfuture use, while the UCl4 thus produced is subjected to furthertreatment, as explained below.

The UC14. produced as a by-product in the molecular still, as explainedabove, is then ground into a finely divided state and placed in asuitable reactor, the UCI4 being. of very fine-grained crystallinestructure. In the reactor, the UCL; is heated to a temperature withinthe range 300 to 350 C. in a stream of dry air. Preferably the stream ofair is. passed through a suitable drier such, for example, as a HaSOebubbler, in order to render it substantially completely free of watervapor. When the UCL; is heated to the elevated temperature mentioned inthe presence of the stream of dry air, it is. reacted by oxidation,whereby the ox'ychloride of uranium, UOaCIz, is produced in crystallineform. The reaction of the UCle.v and the oxygen in the stream of dry airis substantially quantitative and may be written as follows:

This reaction of the UCL; is continued until it is substantiallyentirely converted to UOzClz, which may be carried out ordinarily infifteen or twenty minutes under the conditions mentioned. The UOzClz isthen collected and subjected to further treatment, as explained below;

The UOzClz produced in the reactor, as explained above, is then reactedin an autoclave and convertedv to UCls in a manner substantiallyidentical to that disclosed in the copending application of Ernest C.Evers' and Charles J. Carignan, Serial No. 557,544, filed October 6,1944. More particularly, a dry charge is prepared comprising the UOzClzalone or admixed with a suitable quantity of U03, as makeup material. Inthe event an admixture of UOzClz and U03 is employed, it is arbitraryand without particular reference to proportion. The charge so preparedis then placed in the autoclave, this charge comprising, for example,1500 grams of the mixture of UOzClz and U0 200 grams of UCls, and 3700cc. of CC14 (representing approximately 150% excess of CC14). Theautoclave is closed and the charge is heated directly to C. in anappropriate time interval; after this temperature is held for a time ofone-half hour the charge is further heated in order to cause thetemperature thereofto be raised progressively to 160 C. Moreparticularly, the temperature of. the charge is raised from 120 to C, inone and one-half hours and then from 140" to C. in one and one-fourthhours. Finally, the temperature of the charge is held at 160 C. for.onehalf hour, whereby the total timeof heating the charge above 120C. isthree and three-fourths hours. Throughout the reaction the pressure iskept sutficiently high to maintain carbon tetrachloride in. liquid phasein the reaction zone. The head pressure over the charge is thenrelieved, the excess CC14 is evaporated, and the product is subjected tovacuum and heat in order to substantially completely remove any CCL; andCOClz entrapped therein. When the charge is thus treated, the U0 and theUO'zCl'z are converted substantially quantitatively into UCls, andthereactions may be written as follows:

For example, in the event the charge of 1500 grams of the mixture of U03and UOzClz comprises substantially equal parts of the two compoundsmentioned, approximately 2000 grams of UC15. are produced.

After the charge is thus reacted inthe autoclave to produce UC15' in themanner explained above, it is removed and transferred to the-molecularstill, whereby it is again decomposed into UCl4 and UCls, as previouslyexplained. This cycle of the individual steps described above may berepeated any number of times, whereby therequired quantity of UCls isproduced in batches and the UC14 produced as a by-product incident toeach batch of UCls is re-worked.

Referring now more particularly to Fig. 1 of the drawing, it will beobserved that the entire cyclic process may be carried out in apparatuscomprising a molecular still 10, a reactor 11, and an autoclave 12. Incarrying out the present process the UCl5 placed in the molecular stillis decomposed into the end-product, UCls, and the by-product, UClt, asindicated. The UCl-t is then transferred to the reactor 11 and isreacted with oxygen to produce UO2C12, as indicated. Finally, theautoclave 12 is provided with a charge comprising the UO2C12, U03, UCls,and CCl4, which charge is reacted to produce UC15 and the gas productsCOClz, C0, C02, and C12, the gas products being discharged, asindicated.

In a modified form of the cyclic process, UCls is first decomposed intoUC14 and UCle in the manner disclosed in. the previously mentionedJenkins application. More particularly, a suitable charge of UCls isplaced in a molecular still and treated in the manner previouslydescribed, whereby the desired end-product, UCle, is produced as asublimate, and the by-product, UC14, is produced as a residue.

The UC14 produced as a by-product in the molecular still, as explainedabove, is collected and ground into a finely-divided state, and thenconverted directly into UCls, in the manner disclosed in the abandonedapplication of Horace R. McCombie, Serial No. 506,336, filed October 15,1943, an abstract of which was printed in the Official Gazette ofFebruary 26, 1952.

More particularly, this UCl4 is mixed with make-up UC14, produced in anysuitable manner, the mixture being arbitrary and without particularreference to proportion, to produce a total charge of UCl4 which isplaced in a suitable reactor. The charge of UCl4 in the reactor isheated to a temperature within the range 520 to 550 C. in a dry streamof chlorine. For example, when a charge of 500 grams of UCl4 is treatedin the manner explained above for approximately seven hours, it isconverted substantially quantitatively into approximately 546 grams ofUCl5, and the reaction may be written as follows:

After the charge is thus reacted in the reactor to produce UCls in themanner explained above, it is removed and transferred to the molecularstill, whereby it is again decomposed into UC14 and UCls, as previouslyexplained. This cycle of the individual steps described above may berepeated any number of times, whereby the required quantity of UClsis'produced in batches and the UCl4 produced as a by-product incident toeach batch of UCls is re-worked.

Referring now more particularly to Fig. 2 of the drawing, it will beobserved that this modified form of the entire cyclic process may becarried out in apparatus comprising a molecular still and a reactor 21.In carrying out the present process, the UCls placed in the molecularstill 20 is decomposed into the end-product UCls, and the lay-productUC14, as indicated. Then the reactor 21 is provided with a chargecomprising the UCL; taken from the 'molecular still 20 and additionalUCls produced in any desired manner, which charge is reacted with C12 toproduce UC15, as indicated.

In carrying out this modified form of the cyclic process of producingUCls, the additional UCl4 which is required for make'up purposes in thereactor 21 may be made in any suitable manner, as previously noted.However, it is preferable that this UC14 be made in accordance with theprocess disclosed in U. S. Patent No. 2,677,- 592 issuedto James M.Carter on May 4, 1954. As disclosed in the Carter application, a chargeof 600 grams of U02 is reacted with the required amount of CCl4,

whereby it is converted substantially quantitatively into 844 grams ofUCl4. In this process, the charge of U0: is heated in a suitable reactorto a temperature within the range 425 to 475 C., and contacted with astream of CCl-t vapor heated to a temperature of the order500 C., thereaction requiring approximately four and onehalf hours.

While there has been described what is at present considered to be thepreferred embodiment of the invention, it will be understood thatvarious modifications may be made therein and it is intended to cover inthe appended claims all such modifications as fall within the truespirit and scope of the invention.

What is claimed is: r r

l. The process of producing UCle comprising converting UC15 into UClsand UCl4, converting the UClrinto a uranium oxychloride by reaction witha dry air stream, converting the uranium oxychloride into UCls, and thenrepeating the cycle employing the UC15 thus obtained.

. 2. The process of producing UCle comprising converting UC15 into UCleand UCl4, converting the UCL; into UOaClzby reaction with a dry airstream, converting the UO2Clz into UCls, and then repeating the cycleemploying the UCI5 thus obtained.

3. The process of producing UCls comprising converting a chargeincluding a uranium oxychloride and another uranium compound into UCls,converting the UCls into UCls and UCl4, converting the UCL; intoauranium oxychloride by reaction with a dry air stream, adding to theuranium oxychloride thus obtained sufficient of said other uraniumcompound to produce another charge adapted 7 Theoretical Chemistry, vol.XII,

for conversion to UCls, and then repeating the cycle emplying thelast-mentioned charge.

4. The process of producing UCls comprising converting a chargeincluding a uranium oxychloride and U03 into UCl5, converting the UClsinto UCle and UCl4, converting the UCL; into a uranium oxychloride byreaction with a dry air stream adding to the uranium oxychloride thusobtained sufiicient U03 to produce another charge adapted for conversionto UC15, and then repeating the cycle employing the last-mentionedcharge.

5. The process of producing a uranium oxychloride comprising reactingUCl4. and dry air at an elevated temperature.

6. The process of producing a uranium oxychloride comprising heatingUClt to an elevated temperature in a stream of dry air.

7. The. process of producing a uranium oxychloride comprising heatingUC14 to a temperature within the range 30010 350 C. in a stream of dryair.

8. The process of producing UOzClz comprising reacting UCl4 and dry airat an elevated temperature. 9. Ina cyclic process for producing UCle,the steps comprising converting UCls into UCls and UCl4, converting theUCL; into a uranium oxychloride by reaction with oxygen at an elevatedtemperature, converting the uranium oxychloride into UCls and thenrepeating the cycle employing the UC15 thus obtained.

10. In a cyclic process for producing UCls, thesteps comprisingconverting UCls into UCls and UCl4, converting the UC14 into a uraniumoxychloride by reaction with oxygen at a temperature within theapproximate range of 300 to 350 C., converting. the uranium.0xychlorideinto UCls and then repeating the cycle employing the UCls thus obtained.I

11. The process of producing uranium oxychloride comprising reactingUCl4 and dry gaseous oxygen at an elevated temperature.

References Cited in the file of this patent Mellor: ComprehensiveTreatise, on Inorganic and 1932, pages 83, ,84, and 86. V

1. THE PROCESS OF PRODUCING UCL6 COMPRISING CONVERTING UCL5 INTO UCL6AND UCL4, CONVERTING THE UCL4 INTO A URANIUM OXYCHLORIDE BY REACTIONWITH A DRY AIR STREAM, CONVERTING THE URANIUM OXYCHLORIDE INTO UCL5, ANDTHEN REPEATING THE CYCLE EMPLOYING THE UCL5 THUS OBTAINED,
 8. THEPROCESS OF PRODUCING UO2CL2 COMPRISING REACTING UCL4 AND DRY AIR AT ANELEVATED TEMPERATURE.